1. Field of the Invention
This invention relates generally to low-power circuits and, particularly, to low-power circuits capable of operating at relatively high temperatures.
2. Description of the Related Art
Electronic devices are increasingly designed to have low power or battery power functionality. As a consequence, energy conservation is an important requirement for microcontrollers and other circuits that implement the device features.
Many devices operate in “sleep” or “standby” modes with circuits configured to function with low standby currents, e.g., standby current as low as 9 nA. In some implementations, such circuits are specified to function from −40 C to 85 C. However, some applications, referred to as “extended temperature” applications, require functionality at temperatures up to 150 C. Unfortunately, however, in circuits that burn very low currents, as temperature of operation increases, leakage current increases exponentially. This results in circuit failure because all or most of the bias current flowing in the circuit can leak to ground and/or to the power supply rail.
Thus, historically, there has been a trade off between low current and high temperature operation.